2 close calls last year helped spur revised safety measures

September 26, 2012|By Jon Hilkevitch, Chicago Tribune reporter

After two near-collisions of airliners above O’Hare, new air-traffic procedures are being followed to reduce risks involving takeoffs and landings on two nearby runways, the FAA said. (Zbigniew Bzdak, Chicago Tribune)

The risk of midair collisions at O'Hare International Airport has been significantly reduced as a result of revised air traffic procedures and creation of a "virtual intersection" to better manage two runways where planes land and depart seconds apart, the Federal Aviation Administration said Tuesday.

The FAA's assurances of improved safety at O'Hare followed the release by the National Transportation Safety Board of an update into investigations of two similar close calls three months apart in 2011 in which pilots escaped midair crashes.

Based on the new data, along with radio transmissions and pilot and air traffic controller interviews with NTSB investigators, controller errors appear to be at least partly responsible for the planes flying within several hundred feet of colliding in both incidents, although the safety board has not yet made a final determination.

The focus of the investigation is a critical area of O'Hare where planes approaching to land toward the east on Runway 9 Right cross over at low altitude part of another active runway, 32 Left, where planes are on a high-speed takeoff roll toward the northwest.

The job of air traffic controllers is to safely sequence landings and takeoffs — allowing an arrival to pass over before clearing a takeoff — and to issue new directions quickly if potential problems develop. It is a fast-paced working environment for pilots and controllers at the nation's second-busiest airport, reflected by the fact that apparently none of the passengers on the planes involved in the near-collisions realized they had encountered a close call, officials said.

On May 16, 2011, the pilots of an ExpressJet Airlines plane that was cleared for takeoff on 32 Left suddenly spotted a SkyWest Airlines plane descending toward them, according to the NTSB report. Instead of executing a normal takeoff climb, the ExpressJet crew remained about 100 feet off the ground to let the SkyWest plane pass over.

The SkyWest pilots, who were issued a belated "go-around" order by air traffic control to abort their landing, cleared the ExpressJet by only about 275 feet vertically, the safety board said.

"What the (expletive) was that?" the ExpressJet pilot radioed to O'Hare tower. "Where do you want (us) to go now?"

A controller issued directions, then added, "Sorry about that."

In a subsequent interview with the NTSB, according to the report, the controller said he "forgot about the arrival when he issued (ExpressJet) a takeoff clearance."

Asked by investigators how O'Hare tower managers could help prevent the near-tragedy from happening to a controller-in-training, the controller responded, "Tell the story."

The FAA changes put in place as a result of the incident include issuing an automated warning in O'Hare tower if a plane is near a new "virtual intersection" developed for Runway 32 Left departures and Runway 9 Right arrivals, the FAA said.

Such an alert by the already existing Airport Surface Detection Equipment was not issued in either close call at O'Hare because its software was not programmed to detect a hazard just above the runway, the NTSB said.

Also, pilots who are landing are now being instructed to cut off their approach and go around the airport if they are within 2.75 miles from the end of 9 Right while another plane is on 32 Left, the FAA said. Pilots on 32 Left are now issued a "line up and wait" order before being issued a takeoff clearance, officials said.

The changes will be needed until the O'Hare expansion program is completed, officials said. The 9 Right/32 Left intersection will be eliminated upon the eventual closing of 32 Left under Chicago's plan to reconfigure O'Hare's decades-old crisscrossing runways into a predominantly parallel runway format.

A similar near-collision occurred Aug. 8, 2011, on the same O'Hare runways. As his jet approached takeoff speed, the captain of a Trans States Airlines plane acted quickly to keep the plane on the ground and slightly delay takeoff to avoid a collision with a Chautauqua Airlines plane flying overhead to land, according to the safety board investigation. The Chautauqua plane passed 125 feet over and 350 feet in front of the Trans States plane, the safety board said.

A warning from a controller was issued, but it might have been too late if the Trans States pilots had not taken evasive action on their own to delay their takeoff, they told NTSB investigators.

Some controllers and FAA supervisors interviewed after the incident said an islandlike platform in the middle of the O'Hare tower floor might have obstructed controllers from seeing and coordinating with one another effectively about incoming and outgoing traffic. One controller told the NTSB the platform was like "the elephant in the room."

The platform was removed a few months ago, FAA spokesman Tony Molinaro said. Also, controllers working certain jobs in O'Hare's tower are now positioned closer together to improve communication, he said.